"contrary to past" is correct and usable in written English.
You can use it to refer to something that is different from what happened or took place in the past. For example: "The new policy was contrary to past policy and was met with resistance from many staff members."
Contrary to past speculations that dinosaurs resembled lizards, Mr. Sampson explains, they were in fact more akin to birds.
Contrary to past thinking, Genesereth believes that Herbrand semantics makes it possible to teach the fundamentals of logic in high schools.
In some cases, the board said, companies used assumptions that were contrary to past experience, but the auditor had accepted them without challenge.
Frank J. Fahrenkopf Jr., the commission's Republican co-chairman, said that contrary to past experience, the candidates would not be allowed to change the format.
As the column noted, the drop in unemployment to 4percentt has not caused much inflationary pressure -- contrary to past experience.
Contrary to past predictions, we don't carry smart cards packed with health data; most treatments aren't genetically tailored; and health tourism to Bangalore remains low.
In contrary to the past, computer-based tools are now available that make designing new applications easier.
Contrary to the past, only a handful of citizens turned up to demand new schools for their districts.
Contrary to some past research, time-varying discrepancies in levels of harmful alcohol use between men and women were related to a lower risk of psychological IPV for women and physical IPV for both genders.
And it also flies in the face of history: contrary to legend, past efforts to limit Medicare spending have in fact "stuck," rather than being withdrawn in the face of political pressure.
Contrary to his past statements, he has not signed more bills than any previous president in the first six months, he does not have the biggest defense budget and he has not proposed the biggest tax cut in U.S. history.
